1. Field of the Invention
This invention relates to the use of 1-substituted isatins for coloring keratin-containing fibers, more especially human hair.
2. Discussion of Related Art
In general, keratin-containing fibers, for example hair, wool or pelts, are dyed either with substantive dyes or with oxidation dyes which are formed by oxidative coupling of one or more primary intermediates with one another or with one or more secondary intermediates. Primary and secondary intermediates are also known as oxidation dye precursors.
The primary intermediates normally used are primary aromatic amines containing another free or substituted or amino group in the para or ortho position, diaminopyridine derivatives, heterocyclic hydrazones, 4-aminopyrazolone derivatives and 2,4,5,6-tetraaminopyrimidine and derivatives thereof.
Special representatives are, for example, p-phenylenediamine, p-toluylenediamine, p-aminophenol, o-aminophenol, 1-(2'-hydroxyethyl)-2,5-diaminobenzene, N,N-bis-(2-hydroxyethyl)-p-phenylenediamine, 2-(2,5-diaminophenoxy)-ethanol, 1-phenyl-3-carboxyamido-4-amino-5-pyrazolone, 4-amino-3-methylphenol, 2,4,5,6-tetraaminopyrimidine, 2-hydroxy-4,5,6-triaminopyrimidine, 4-hydroxy-2,5,6-triaminopyrimidine, 2,4-dihydroxy-5,6-diaminopyrimidine, 2-dimethylamino-4,5,6-triaminopyrimidine, 2-hydroxyethylaminomethyl-4-aminophenol, 4,4'-diaminodiphenylamine, 4-amino-3-fluorophenol, 2-aminomethyl-4-aminophenol, 2-hydroxymethyl-4-aminophenol, bis-(2-hydroxy-5-aminophenyl)-methane, 1,4-bis-(4-aminophenyl)diazacycloheptane, 1,3-bis-(N-(2-hydroxyethyl)-N-(4-aminophenylamino))-2-propanol, 4-amino-2-(2-hydroxyethoxy)-phenol and 4,5-diaminopyrazole derivatives according to EP 0 740 741 or WO 94/08970, for example 4,5-diamino-1-(2'-hydroxyethyl)-pyrazole.
The secondary intermediates used are generally m-phenylenediamine derivatives, naphthols, resorcinol and resorcinol derivatives, pyrazolones and m-aminophenols. Particularly suitable secondary intermediates are 1-naphthol, pyrogallol, 1,5-, 2,7- and 1,7-dihydroxynaphthalene, o-aminophenol, 5-amino-2-methylphenol, m-aminophenol, resorcinol, resorcinol monomethyl ether, m-phenylenediamine, 1-phenyl-3-methyl-5-pyrazolone, 2,4-dichloro-3-aminophenol, 1,3-bis-(2,4-diaminophenoxy)propane, 4-chlororesorcinol, 2-chloro-6-methyl-3-aminophenol, 2-methyl resorcinol, 5-methyl resorcinol, 2,5-dimethyl resorcinol, 2,6-dihydroxypyridine, 2,6-diaminopyridine, 2-amino-3-hydroxypyridine, 2,6-dihydroxy-3,4-diaminopyridine, 3-amino-2-methylamino-6-methoxypyridine, 4-amino-2-hydroxytoluene, 2,6-bis-(2-hydroxyethylamino)-toluene, 2,4-diaminophenoxyethanol, 1-methoxy-2-amino-4-(2-hydroxyethylamino)-benzene, 2-methyl-4-chloro-5-aminophenol, 6-methyl-1,2,3,4-tetrahydroquinoxaline, 3,4-methylenedioxyphenol, 3,4-methylenedioxyaniline, 2,6-dimethyl-3-aminophenol, 3-amino-6-methoxy-2-methylaminophenol, 2-hydroxy-4-aminophenoxyethanol, 2-methyl-5-(2-hydroxyethylamino)-phenol and 2,6-dihydroxy-3,4-dimethyl pyridine.
With regard to the dyes suitable for use in the hair coloring and tinting formulations according to the invention, reference is also specifically made to Ch. Zviak's work The Science of Hair Care, Chapter 7 (pages 248-250; Substantive Dyes) and Chapter 8, pages 264-267; Oxidation Dye Precursors), published as Vol. 7 of the Series "Dermatology" (Editors: Ch. Culnan and H. Maibach), Marcel Dekker Inc., New York/Basel, 1986 and to the "Europaische Inventar der Kosmetik-Rohstoffe" published by the Europaische Gemeinschaft and available in diskette form from the Bundesverband Deutscher Industrie- und Handelsunternehmen fur Arzneimittel, Reformwaren und Korperpflegemittel e.V., Mannheim, Germany.
Although intensive colors with good fastness properties can be obtained with oxidation dyes, the color is generally developed under the influence of oxidizing agents, such as H.sub.2 O.sub.2 for example, which in some cases can result in damage to the fibers. In addition, some oxidation dye precursors or certain mixtures of oxidation dye precursors can occasionally have a sensitizing effect in people with sensitive skin. Although substantive dyes are applied under more moderate conditions, their disadvantage is that, in many cases, the colors obtained have inadequate fastness properties.
International patent applications WO 93/19725, WO 94/24988, WO 94/24989 and WO 95/24886 describe formulations for coloring keratin-containing fibers which contain isatin derivatives as their dye component.
The problem addressed by the present invention was to provide colorants for keratin fibers, more especially human hair, which would be at least equivalent in quality to conventional oxidation hair dyes in regard to depth of color, grey coverage and fastness properties, but which would not necessarily have to contain oxidizing agents, such as H.sub.2 O.sub.2 for example. In addition, the colorants according to the invention would have very little, if any, sensitizing potential.